/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.connector.file.sink;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.io.SimpleVersionedSerialization;
import org.apache.flink.core.io.SimpleVersionedSerializer;
import org.apache.flink.core.memory.DataInputDeserializer;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputSerializer;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.streaming.api.functions.sink.filesystem.InProgressFileWriter;

import java.io.IOException;

import static org.apache.flink.util.Preconditions.checkNotNull;

/**
 * Versioned serializer for {@link FileSinkCommittable}.
 */
@Internal
public class FileSinkCommittableSerializer
		implements SimpleVersionedSerializer<FileSinkCommittable> {

	private static final int MAGIC_NUMBER = 0x1e765c80;

	private final SimpleVersionedSerializer<InProgressFileWriter.PendingFileRecoverable> pendingFileSerializer;

	private final SimpleVersionedSerializer<InProgressFileWriter.InProgressFileRecoverable> inProgressFileSerializer;

	public FileSinkCommittableSerializer(
			SimpleVersionedSerializer<InProgressFileWriter.PendingFileRecoverable> pendingFileSerializer,
			SimpleVersionedSerializer<InProgressFileWriter.InProgressFileRecoverable> inProgressFileSerializer) {
		this.pendingFileSerializer = checkNotNull(pendingFileSerializer);
		this.inProgressFileSerializer = checkNotNull(inProgressFileSerializer);
	}

	@Override
	public int getVersion() {
		return 1;
	}

	@Override
	public byte[] serialize(FileSinkCommittable committable) throws IOException {
		DataOutputSerializer out = new DataOutputSerializer(256);
		out.writeInt(MAGIC_NUMBER);
		serializeV1(committable, out);
		return out.getCopyOfBuffer();
	}

	@Override
	public FileSinkCommittable deserialize(int version, byte[] serialized) throws IOException {
		DataInputDeserializer in = new DataInputDeserializer(serialized);

		switch (version) {
			case 1:
				validateMagicNumber(in);
				return deserializeV1(in);
			default:
				throw new IOException("Unrecognized version or corrupt state: " + version);
		}
	}

	private void serializeV1(
			FileSinkCommittable committable,
			DataOutputView dataOutputView) throws IOException {

		if (committable.hasPendingFile()) {
			dataOutputView.writeBoolean(true);
			SimpleVersionedSerialization.writeVersionAndSerialize(
					pendingFileSerializer,
					committable.getPendingFile(),
					dataOutputView);
		} else {
			dataOutputView.writeBoolean(false);
		}

		if (committable.hasInProgressFileToCleanup()) {
			dataOutputView.writeBoolean(true);
			SimpleVersionedSerialization.writeVersionAndSerialize(
					inProgressFileSerializer,
					committable.getInProgressFileToCleanup(),
					dataOutputView);
		} else {
			dataOutputView.writeBoolean(false);
		}
	}

	private FileSinkCommittable deserializeV1(DataInputView dataInputView) throws IOException {
		InProgressFileWriter.PendingFileRecoverable pendingFile = null;
		if (dataInputView.readBoolean()) {
			pendingFile = SimpleVersionedSerialization.readVersionAndDeSerialize(
					pendingFileSerializer,
					dataInputView);
		}

		InProgressFileWriter.InProgressFileRecoverable inProgressFileToCleanup = null;
		if (dataInputView.readBoolean()) {
			inProgressFileToCleanup = SimpleVersionedSerialization.readVersionAndDeSerialize(
					inProgressFileSerializer,
					dataInputView);
		}

		return new FileSinkCommittable(pendingFile, inProgressFileToCleanup);
	}

	private static void validateMagicNumber(DataInputView in) throws IOException {
		int magicNumber = in.readInt();
		if (magicNumber != MAGIC_NUMBER) {
			throw new IOException(String.format(
					"Corrupt data: Unexpected magic number %08X",
					magicNumber));
		}
	}
}
